An opening or gap is purposely provided between adjacent structural members for accommodating dimensional changes within the gap occurring as expansion and contraction due to temperature changes, and/or seismic cycling and vibration. An expansion joint system is conventionally installed in the gap to provide a bridge across the gap and to accommodate the movements in the vicinity of the gap.
Bridge and roadway constructions are especially subject to relative movement in response to the occurrence of thermal changes, seismic events, and vehicle loads. This raises particular problems, because the movements occurring during such events are not predictable either with respect to the magnitude of the movements or with respect to the velocity of the movements. In some instances bridges have become unusable for significant periods of time, due to the fact that traffic cannot travel across damaged expansion joints.
Known expansion joint systems utilize a movable rubber seal and a steel cover plate to bridge an expansion joint gap. The steel cover plate is fixedly bolted to the rubber seal member. Because the cover plate and rubber seal are bolted together, movement of the expansion joint system in the traverse direction (the direction perpendicular to the direction of traffic across the expansion joint) is severely constrained. Limited transverse movement may only be accomplished through pushing and shearing of the rubber seals. What is needed in the industry is an expansion joint system that is able to accommodate larger movements in the transverse direction.